1. Field of the Invention
The present invention relates to a method for controlling at least one member of a vehicle. It also relates to a system for this control as well as a vehicle which is equipped therewith. The member may be, for example, a road lighting device of the vehicle, the method making it possible to control the beam of this lighting.
2. Description of the Related Art
Its preferred application is the automobile industry, notably to equip vehicles with light projection for lighting the road in front of the driver.
The quality of the road lighting by the vehicles in traffic is a fundamental element both for visual comfort and for the safety of road movements. For a long time, automobile equipment has been limited to providing several beams of code, low beam and high beam or even fog beam type. These beams are conventionally controlled by the driver by means of a purely manual switching control. It occupies the driver's attention when the driving conditions generally implied by the management of the headlights—journeys at night, in bad weather, for example—already merit all his or her concentration. Human capabilities are not such that the control of the lighting can best be managed in all circumstances.
To remedy this, some systems use speed thresholds to switch from one beam state to another. Speed information is very clearly insufficient for characterizing a driving context and the lighting state that it implies.
Lighting devices implementing automatic controls have already been proposed with the use of navigation information. The navigation systems associate mapping data and location information supplied by a device of the GPS (Global Positioning System) type. It is thus possible to know in advance the geometry of the traffic lane and certain road context conditions, for example, the entry onto a freeway. Lighting devices exploit this information to control the beams. In particular, one technology handles the automatic switching between an activated state of a freeway lighting beam and a deactivated state depending on the recognition of the type of traffic lane used by the vehicle.
It has been found, however, that this automated beam control mode is not without its drawbacks. The location offered by a GPS system has a limited resolution (generally of the order of ten or so meters), so that the beam control can take into account only traffic conditions that change little and often with delays. As an illustration, an occasional change of traffic conditions linked to a slow-down on a freeway cannot be effectively reflected in the lighting control to deactivate the freeway lighting beam in real time. Moreover, the mapping data are not totally reliable because of potential errors in their construction or subsequent physical modifications to the traffic lanes. These imperfections, inherent in the GPS technology, are all the more of a hindrance when the lighting control impinges on road safety issues.